Process for preparing polymeric blends



July 29, 1969 Filed Dec. 31, 1962 L. W. POLLOCK PROCESS FOR PREPARING POLYMERIC BLENDS 4 Sheets-Sheet 1 .RECYCLE STYRENE LP BUTADIENE\ J RECYCLE BUTADIENE ,.c

STYRENE EMULSION BUTADIENE STYRENE WATER: A POLYMERIZATION FLASH STRIPPER REAcTOR B EMULSIFIER SYSTEM |2 |3 CATALYST: s

CHEMICALS:

WATER F 18' BUTADIENE M H SOLUTION TOLUENE} POLYMERIZATION z REACTOR g CATALYST SYSTEM 2 SHORT STOP) c '6 ANTIOXIDANT Gx 2 T I9 S 1 w 1 LATEx FLASH 4 RECYCLE TOLUENE J & BUTADIENE v E sOLuTTON I A 17 BLENDING K |6- STEAM {WET TOLUENE STRIPPING WATER v 2. 4 f l5 0 DEWATERING DRYING 1 PRODUCT BLEND 22 WATER INVENTOR.

L. W. POLLOCK ATTORNEYS July 29, 1969 L. w'; POI-LOCK PROCESS FOR PREPARING POLYMERIC BLENDS 4 Sheets-Sheet 4 Filed Dec. 31. 1962 dOkUaQE ZQWJDEM HBddlhLLS HBMdCI INVENTOR.

L. W. P0 LLOC K moku wm ZOFPDJOW A T TORNEYS United States Patent 3,458,602 PROCESS FOR PREPARING POLYMERIC BLENDS Lyle W. Pollock, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware Filed Dec. 31, 1962, Ser. No. 248,766 Int. Cl. (108d 9/02 US. 'Cl. 260880 2 Claims ABSTRACT OF THE DISCLOSURE Various techniques are disclosed for preparing blends of polymers from ethylenically unsaturated compounds. Thus, a blend of a polymer prepared by solution polymerization and a polymer prepared by emulsion polymerization is produced by preparing one of the polymers and adding it to the feed to a reaction zone in which the other polymer is made. Where the emulsion polymer is to be added to the solution polymerization zone, the latex is treated with a solvent to extract the polymer and the resulting solution is fed to the solution polymerization zone along with the monomer to be polymerized there.

This invention relates to producing a blend of two or more polymer compositions. In one aspect the invention relates to a process for blending a solution polymer and an emulsion polymer. In another aspect the invention relates to a process for the production of a blended polymer composition. In another aspect the invention relates to polymer blends.

To utilize the many varieties of polymers most efiectively, in many instances it is desirable to produce polymer blends. Such blends make it possible to take advantage of desirable qualities of the various polymers blended. For example, high cis-content polybutadiene is blended with SBR for use in automobile tires to improve wear, prevent groove cracking and retard ozone attack of tire treads, improve carcass durability and lower operating temperature.

An object of my invention is to blend polymer compositions.

Another object of my invention is to blend a solution polymer and an emulsion polymer economically and efficiently.

Another object of my invention is to produce a blended polymer composition.

Another object of my invention is to blend solutionpolymerized butadiene with emulsion-polymerized SBR.

Other aspects, objects and the advantages of my invention are apparent in the written description, the drawing and the claims.

According to my invention a blend of a solution-polymerized polymer and an emulsion-polymerized polymer is produced by the steps of producing one of the polymers and adding it to the feed to a reaction zone in which the other polymer is made.

Where the emulsion-polymerized polymer is to be added to the solution polymerization reaction zone, the latex resulting from the emulsion polymerization is contacted with a water immiscible solvent to remove the polymer, and the resulting polymer solution is fed to the solution polymerization zone along with the monomer to be polymerized there.

The solution-polymerized polymer, on the other hand, can be added to the emulsion polymerization reaction zone. When this is done, to avoid the necessity for emulsifying unnecessarily large amounts of hydrocarbon, I prefer to use as a solvent in the solvent polymerization reaction zone a monomer which is to be polymerized in the emulsion polymerization zone. This process is utilized very effectively in those instances wherein the monomer ice polymerized in the solution polymerization zone also is a monomer to be polymerized in the emulsion polymerization zone, in which instance a partial polymerization of this monomer in a liquid phase is carried out in the solution zone, the resulting solution of polymer in the monomer being fed into the emulsion polymerization zone. For example, my invention is applicable to a solution polymerization of butadiene followed by an emulsion polymerization of butadiene and styrene to form SBR. In this instance a partial polymerization of butadiene in liquid phase is carried out in the solution polymerization zone, and the solution of polybutadiene in butadiene fed to the emulsion polymerization zone. Additional advantages are gained by adding water to the efiluent from the solution polymerization zone followed by a flashing of a portion of the unpolymerized monomer prior to feeding to the emulsion polymerization zone.

Also, according to my invention, the latex from an emulsion polymerization is extracted with a solvent to remove the polymer, and the resulting solution added to the product solution from a solution polymerization.

According to my invention, at least one of the polymers to be blended is formed in an emulsion system while the other can be formed in an emulsion system or a solution system. Examples of polymers formed by solution polymerization suitable for the practice of my invention include polybutadiene, polyisoprene, polyethylene, polyisobutylene, polystyrene, ethylene-propylene rubber, and block copolymers such as are described in Ser. No. 796,277 filed Mar. 2, 1959. Examples of polymers formed by emulsion polymerization suitable for the practice of my invention include styrene-butadiene rubber, butadienevinylpyridine rubber, polyvinylchloride, polystyrene, polyacrylonitrile, polyvinylacetate, and butadiene-acrylonitrile copolymer. Some of the blends which are now known to be useful include blends of high 'cis content polybutadiene with SBR, polyvinylchloride with polyethylene, and polyacrylonitrile with polybutadiene. Of course, other blends can be made from the above and other polymers.

In the drawing, FIGURE 1 is a diagrammatic sketch of a system in which the latex resulting from an emulsion polymerization is extracted with a solvent and the resulting solution blended with the product solution of a solution polymerization.

FIGURE 2 is a diagram of a system in which the latex resulting from an emulsion polymerization is extracted with a solvent and the resulting solution added to thefeed to a solution polymerization reactor system.

FIGURE 3 is a diagram of a system in which the solu-- tion resulting from a solution polymerization is added.- to the feed to an emulsion polymerization reactor system.

FIGURE 4 is a diagram of another system in which the solution product from a solution polymerization system is added to the feed to an emulsion polymerization system, water being added prior to flashing unreacted monomer.

In the system illustrated in FIGURE 1, the various ingredients for an emulsion polymerization reaction are fed into the emulsion polymerization reactor system 11. In the particular system illustrated the monomers comprise butadiene and styrene and the product is styrenebutadiene rubber (SBR). The product from the reactor system is fed to a flash zone 12 wherein unreacted butadiene is removed and recycled. The resulting product then is fed to a styrene stripper 13 from which unreacted styrene is returned to the system and the product fed to extraction column 14. In column 14, the latex is contacted with wet toluene from a steam stripper 16 and the rubber is dissolved and fed into a solution blending zone 17 While water is removed from the top of column 14. Butadiene, toluene and a catalyst are fed into solution polymerization reactor system 18 wherein a high 3 cis content polybutadiene is formed and removed therefrom to flash zone 19. A shortstop for the reaction and an antioxidant are added to the product as shown. The resulting solution of polybutadiene in toluene is fed into solution blending zone 17 where it is blended with the isobutylaluminum, iodine, and titanium tetrachloride in the mol ratio of 11:3:1. The reaction is maintained at a temperature of 55 F. and a pressure of 140 p.s.i.a. The shortstop, rosin acid, and an antioxidant, 2,2-methylene bis(4-ethyl-6-tertiarybutyl phenol), are fed into the efliusolution of SBR from extraction column 14 and the comcut as shown and the product passed to flash system 19. bined stream fed to steam stripping zone 16 from which Here butadiene and toluene are removed at a pressure of toluene is removed. The stream then is fed into a dewater- 18 p.s.i.a. and a temperature of 240 F. and recycled to ing means 21 which can be, for example, a water expeller, the reactor system. The remaining solution of high cis and the relatively dry product further dried in a drying content butadiene in toluene is fed to solution blending means 22, from which the dry product blend is recovered. zone 17 Where it is blended with the solution from extrac- Example I tion column 14 at 150 F. The blended solutions are fed to steam stripping zone 16 which is operated in two In an example, according to the illustration of FIG- stages, the first stage at p.s.i.a. and 205 F. and the URE 1, butadiene, styrene, water, a catalyst, an emulsi- 15 second stage at 18 p.s.i.a. and 220 F. The polymer fier, and other chemicals are fed into the emulsion polymblend then is fed to dewatering means 21 which in this erization reactor system. example is a water expeller operated at 150 F. from In this example the catalyst comprises ferrous sulfate which excess water is removed. The partially dry polymer heptahydrate, sodium formaldehyde sulfoxylate and pthen is fed to drying means such as an extruder dryer methane hydroperoxide. The emulsifier is a potassium 22 wherein the remainder of the water is removed. The fatty acid soap. The chemicals include a buffer, potassium amounts of the various components in the various streams chloride; a disperser, a sodium salt of naphthalene sulare given in Table I, the amounts being in pounds per tonic acid condensed with formaldehyde; a sequestering 2000 pounds of dry blended polymer.

TABLE I A B o D E F G H I Cis- Cistfiiii tfiii: Styrene Water Solvent diene diene Reactor Reactor Recycle stripper Rubber item to reactor reactor feed eflluent butadiene bottoms extract extractor extractor change efliuent Butadiene 1,260 480 460 1,250 250 Cis-polybutadiene Blended Polymer- Partially Dr Styrene flash polymer Wet water dewatered product stripper bottoms solution toluene slurry rubber blend overhead Emulsifier-.. 42 42 20 20 Butadiene- 6 Total 1 Letters from FIGURE 1.

agent, a tetrasodium salt of ethylenediamine tetraacetic acid; and a modifier, tertiary dodecyl mercaptan. In this example, 16 pounds of catalyst and 3 pounds of chemicals are used. Following the reaction a shortstop, a mixture of sodium polysulfide and sodium dimethyl dithiocarbamate, and an antioxidant, a mixture of alkylated aryl phosphites, are added.

In the reactor system a copolymer of the butadiene and styrene, SBR, is formed. Following flashing of excess butadiene, excess unreacted styrene is stripped and the resulting latex fed to extraction column 14. Reactor system 11 is maintained at a temperature of 41 F. and a pressure of 140 p.s.i.a. The butadiene flash is in two stages, the first stage at 90 F. and 20 p.s.i.a. while the second stage is at 90 F. and 180 mm. Hg. Styrene stripper 13 is operated at a pressure of 90 mm. Hg. and a temperature of 130 F. Wet toluene from steam stripping zone 16 is fed to extraction column 14 where it is contacted with the SBR latex at a temperature of 120 F. and a pressure of 20 p.s.i.a. The solution of SBR in toluene is blended in blending means 17 with the solution of the high cis polybutadiene polymer formed in solution polymerization reactor system 18. Butadiene, toluene and a catalyst are fed to zone 18. The catalyst comprises tri- FIGURE 2 illustrates a system in which an extracted emulsion polymer is included with the feed to a solution polymerization system to produce a blended polymer product. In this system an emulsion polymer, produced in emulsion reactor train 22, is passed to flash means 23 or directly to extraction column 24. In this column the polymer is extracted from the latex, the resulting solution being passed after further processing as feed to a subsequent polymerization zone, the water being removed to waste or recycled to reactor train 22. The solution from extraction column 24 is passed through water wash system 26, comprising homogenizer 27 and phase separator 28, to drying column 29. The dried solution from column 29 is introduced into the feed to solution reactor train 31. The eflluent from reactor train 31 is passed through a flash system 32 and a stripper 33 to dewatering apparatus 34 and dryer 36. From stripper 33 a portion of the overhead product, comprising solvent and monomer, is passed to extraction column 24, and a portion to the drying column 37 and splitter 38 from which the monomer is recycled to emulsion system 22 while the solvent is recycled to the solution system 31. Phase separators 30, 35, and 39 are provided as shown.

Example II In an example of the operation according to FIGURE 2, reactor train 22 is maintained at a temperature of 41 F. and a pressure of 140 p.s.i.a. maximum. The feed compolymer is produced in reactor 41, passed through a flash system 42 and fed into homogenizer 43, which prepares the feed for an emulsion polymerization in reactor 44. The efiiuent from reactor 44 is passed through a flash system 46, a stripper 47, dewatering means 48 and dryer means prises water, butadiene, styrene, emulsifier, a catalyst and 5 49 The overhead from Sm 47 is returned to homo chemicals. The catalyst emulsifier. chem1 cals, shortstop eni'zer 43 While the gfi flashed from flash systeil and antioxidant are the same as that utilized in reactor 46 is passed through a drying column 51 and returned to 11 of FIGPRE 1 m EKamP thls example flash the feed to reactor 41. Phase separators 40, 45, and 50 system 23 1S by-passed and the entlre eflluent from sysare Provided tem 22 passed into extraction column 24. Here the SBR polymer is extracted by a stream of toluene from stripper Example III 32 while water is removed overhead, the column being In an example, according to the system of FIGURE 3, maintained at 120". F. and 140 p. s. .a. The OSOlUtlOll 1s butadiene and a catalyst comprising triisobutylaluminum, wasiled and Passed to dryer 29 13 at 200 65 15 iodine and titanium tetrachloride as used in Examples I P- T dry Stream compnsme toluene and R and II above, are fed into reactor 41 which is maintained along Wlth some unreacted butad 1ene Styrene 18 at a temperature of 55 F. and a pressure of 140 p.s.i.a. Passed 9 reactor syste m 31 wllfh bfltadlenet toluene The effluent is passed into flash means 42 which is a twoand a tnisobutylalummum, lodlne, titanium tetrachloride Stage flash means the first Stage being at and 59 catalyt as'used Example The Pglymerlzatlon of 20 p.s.i.a. while the second stage is at 32 F. and 18 p.s.i.a. butadiene 1s earned out at 40 to 125 F. and 140 p.s.1.a. The emuent f flash System 42 i passed i homogen- The eflluent from reactor tram 31 is passed through flash izi,r 43 Wham it is blended i Styrene Water, an l- Z011e 32 Where osome butadleqet Styrene and {01116116 sifier, a catalyst for the emulsion polymerization reaction, removed'flt f and P- and the remainder b61113 and other chemicals, the catalyst, emulsifier and chemi- P q to PPF PP 33 TePrcSent a f cals being the same as utilized in the emulsion polymer- StTIPPIIIg Operatwn, the first stage 15 P' and 205 ization of Examples I and II. The blended stream of and the Second Stage at 13 P- and emulsion is produced at a temperature of 40 F. and product steam from stripper comprises substantially all p s i a and passed into reactor here the polymeriza- 0 the SBR PP Y from reactor-22 and the hlgh F tion reaction is carried out at a temperature of 40 F. content butadlene P Y F from reactor 1, along W11 30 and p.s.i.a The effluent from reactor 44 is flashed in a small amount of chemicals and tolueneand a sub t zone 46 which is a two-stage flash, the first stage being at nal amount of water- The stream 15 pertlally dewatered 100 F. and 1s p.s.i.a while the second stage is at 100 F. at F. m water e p the remamder f and mm. Hg. The product stream then is passed into Water belflg removed 111 dfylng meqlls The Varlous stripper 47 and the slurry from stripper 47 passed to amounts 111 the several streams are glv n In T l II, the 35 dewatering means 48, which in this instance is a water amounts being in pounds per 2,000 pounds of dry polyexpeller, and to dryer 49. Butadiene removed and flashed mer blend produced. from zone 46 is dried and recycled to reactor 41 while TABLE II A1 B o D E F G H I J SBR SBR Recycle one (Dis-4 Basis=2000# Pol er reactor reactor SBR E t to W t Component ym feed efifluent butadiene x ised Extract Solvent plia e e355? Maggi e fliii tir ii Butadiene 1,260 480 250 its 3g 38 860 0 ll 11 Water 3,360 3,360 Catalyst 1c 16 i6 Chemicals 87 87 5 82 6 5 5 SBR polymer. 1, 000 1, 000 l, 000 l, 000 1, 000 (Dis-4 polymer. 1, 000

Total 5,163 5,163 12,515 10,820 3,452 12, 505 24,875 24,875

K L M N 0 P Q R Recycle Stripper Partially Basi =2000# Poly er cis4 Flash bottoms dewatered Blend Wet Recycle Recycle Component butadiene bottoms slurry rubber product solvent styrene toluene Butadiene Styrene Toluene. Water Catalyst Chemicals Z... SBR Polymer (Dis-4 Polymer...

Total 9, 594 15, 301 27 045 2, 265

1 Letters from Figure 2. 2 Includes emulsifiers, shortstop antioxidant, etc.

In the system of FIGURE 3, a solution of a polymer produced in a solution polymerization reaction is combined with the feed to an emulsion polymerization system stryrene and the remaining amount of butadiene removed in stripper 47 are returned to homogenizer 43. The amounts of the various streams are given in Table III to produce a blended polymer. In this figure a solution 75 in pounds.

TABLE III A B C D E F G H I .l K L Cis- Cispolybupolybu- Homogtadiene tadiene enize Reactor reactor reactor Recycle Flash total feed Reactor Recycle Flash Recycle Dried teed efiiuent butadiene bottoms feed SBR efiluent butadiene bottoms styrene Slurry product Butadiene 10, 000 9, 000 4, 000 4, 000 4, 000 Styrene 1, 000 1,000 Water t t i t 8, 000 8, 000 Catalyst 10 10 20 Chemicals. 100 100 (Dis-4 polymer 1. l, 000 1, 000 1, 000 1, 000 SB R polymer r.

Total 10, 010 10, 010 5, 000 5, 010 14, 120 14, 120

1 Letters from Figure 3.

In the system of FIGURE 4 the polymerization steps are carried out substantially as in the system of FIG- URE 3. However, water is added to the effiuent from the solution reactor to assist in the flash step, the water then being available as needed in the emulsion polymerization step.

Example IV In an example, according to FIGURE 4, the solution polymer is high cis content polybutadiene and the polymer produced in the emulsion reactor is SBR, the process being carried out substantially as in Example III, with the difference that water is added prior to the first flash step.

Of course, in all systems, components incompatible with the subsequent polymerization reaction must be removed. Such components are known in the art and it is not necessary at this time to attempt to name all of the many such components which might be harmful to known polymerization reaction. My invention is applicable to the blending of compatible polymers.

Reasonable variation and modification are possible within the scope of my invention which sets forth process for blending emulsion and solution polymers and a process for producing a polymer blend.

I claim:

1. A process for producing a blended polymer com- The amonts of various materials in the steps of the process position, which comprises:

are given in Table IV in pounds.

TABLE IV A B C D E F G H I J K L M Butadlene 10,000 300 8,700 1,300 Styrene 20 430 Catalyst Chemicals Polymer cis-4 Polymer SBR Water..-

Total 10,030 10,030 8,000 18,030 9,330 8,700 10,842 10,842 530 10,312 10,122 190 9,230

1 Letters from Figure 4.

Although my invention is applicable to systems in which one or more of the monomers of a polymer which is added to a subsequent polymerization reaction zone is different from the monomer or monomers in subsequent zone, particular advantages accrue in a system in which all of the monomers of the first polymer are utilized in the second polymerization. For example, when the first polymerized mixture is a polymer of butadiene and the second polymerized material is a polymer or a copolymer of butadiene, complete separation of unreacted monomer from the first reaction need not be made. Examples III and IV illustrate systems in which this is true. The solution reaction is a polymerization of butadiene which is one of the monomers utilized in the emulsion polymerization involving butadiene and styrene.

position, which comprises:

partially polymerizing a liquid l-olefin monomer, to produce a first polymer in solution in said monomer;

adding water to the resulting solution of said first polymer in said liquid monomer to produce a mixture of said water and said solution;

flashing excess unreacted monomer from said mixture;

adding to the remaining mixture a second monomer;

feeding said remaining mixture containing said second monomer into a reaction zone wherein said monomer and said second monomer are copolymerized to produce a copolymer compatible with said first polymer; and

recovering from the effluent from said reaction zone,

a blend comprising said first polymer and said copolymer, wherein the first polymer is a polymer of butadiene and the second polymer is styrene butadiene rubber.

References Cited UNITED STATES PATENTS FOREIGN PATENTS Canada.

GEORGE F. LESMES, Primary Examiner US. Cl. X.R. 

